Some electronic devices are capable of recognizing the positional relationship of a plurality of electronic devices based on the communication state. Examples of such electronic devices include mobile telephones such as smartphones, personal digital assistants (PDAs), personal computers (PCs), and television broadcast receivers. For example, such an electronic device measures a distance to an adjacent electronic device based on the radio electric field strength of wireless communication, the delay time, and the like, and determines the position of the adjacent electronic device based on the measurement result. The electronic device then sets a specific electronic device to a reference coordinate system and determines the position of each electronic device.
With the conventional technology descried above, in the case of, for example, wireless communication, high positioning accuracy cannot be expected due to a multipath issue and the like. Besides, in the case of infrared communication, because of the strong directivity, if devices face each other such that a light emitter and a light receiver come face to face with each other, the positional relationship can be defined. On the other hand, if the light emitter and the light receiver are not in a face-to-face position, or there is an obstacle between the devices, it is not easy to determine the accurate positional relationship.